The invention relates to a single-pivot type suspension strut axle for a motor vehicle, particularly for a passenger car, having a wheel carrier or pivot bearing carrying the wheel and a brake disk non-rotatably connected with the wheel with respect to the axis of rotation of the wheel, to which wheel carrier or pivot bearing the suspension strut is fastened. The suspension unit, with its other end, is supported at the vehicle body, and is further guided by way of a supporting joint situated close to the wheel center plane by a lower control arm functionally representing an A-arm and is furthermore guided by a tie rod. Concerning the technical background, reference is made particularly to German Patent Document DE 30 12 873 A1, as well as to German Patent Document DE 197 21 878 A1, to German Patent Document DE 29 27 486 A and to German Patent Application 10 2009 014 879.5, which is not a prior publication.
High demands with respect to driving dynamics and driving comfort are made on the axle constructions of higher-value vehicles. A spring strut type axle or a twin control arm axle is therefore usually selected for driven front axles, which, however, both have system-related disadvantages. Thus, a spring strut type axle has a relatively large overall height, while the construction expenditures for twin control arm axles are relatively high.
The so-called suspension strut axles of the so-called single-pivot type may be more advantageous here, in which case, however, demands, that are difficult to implement constructively, are made on the position of the so-called supporting joint, in which a control arm (in the following called “control arm”) situated at the bottom is connected with the so-called pivot bearing (if a front axle with steerable wheels is involved) or the so-called wheel carrier (if a rear axle is involved). Specifically, as correctly indicated and substantiated in the initially first-mentioned German Patent Document DE 30 12 873 A1, this supporting joint called a “wheel joint” should be situated there as low as possible at least almost in the wheel center plane. In that document, a horizontal distance between the supporting joint and the wheel center plane of only 20 mm measured in the transverse direction of the vehicle is mentioned as an example.
However, such a narrow horizontal distance measured in the transverse direction of the vehicle between the supporting joint and the wheel center plane, which under all types of stress causes only a slight interfering bending moment upon the suspension strut, can in reality hardly be achieved constructively by way of the conventionally designed known wheel suspensions or axle constructions.
Therefore, a suspension strut axle needed where the supporting joint can be arranged in a constructively well implementable manner in close proximity to the wheel center plane, in which case it should be explicitly pointed out that this “close proximity”, i.e. the horizontal distance measured in the transverse direction of the vehicle does not have to be equal to the 20 mm indicated in the above-mentioned document, but can definitely also be in the range of between 0 mm and 40 mm.
For achieving this and other objects, a single-pivot type suspension strut axle for a motor vehicle is provided, particularly for a passenger car, having a wheel carrier or pivot bearing carrying the wheel and a brake disk non-rotatably connected with the wheel with respect to the axis of rotation of the wheel, to which wheel carrier or pivot bearing the suspension strut is fastened which, with its other end, is supported at the vehicle body, and which is further guided by way of a supporting joint situated close to the wheel center plane by a lower control arm functionally representing an A-arm and is furthermore guided by a tie rod. The brake disk is constructed as a ring, through which the control arm projects by way of its section connected with the supporting joint.
According to the invention, deviating from the construction having a so-called brake disk chamber customary in the case of passenger cars, the brake disk is constructed without such a brake disk chamber and therefore represents a ring—as in the construction known from motorcycles—, which ring is constructed in a suitable manner with the wheel in its exterior edge area. A caliper, which carries the brake pads and, if required, presses the latter against the brake disk, in the process reaches around the brake disk from the interior, i.e. from the direction of its radially inner ring edge area. A corresponding exemplary construction of such a wheel assembly of a motor vehicle is illustrated in the above-mentioned German Patent Application 10 2009 014 879.5, which is not a prior application.
As a result of the fact that, according to the invention, the above-mentioned supporting joint, viewed in the transverse direction of the vehicle from the center plane of the vehicle, is situated outside the brake disk, the supporting joint can be arranged very close to the wheel center plane because the brake disk or its (in the present case, absent) chamber does not have to be taken into account. In this case, an arrangement of the brake disk that is quasi-inside such a supporting joint of a wheel carrier, i.e. between the supporting joint and the vehicle center plane, is already known—compare, for example, German Patent Document DE 15 55 234 A or European Patent Document EP 0 402 777 B. However, this state of the art does not concern a single-pivot suspension strut axle, and, in particular, no control arm extends through the brake disk, but in the prior art, control arms extend around this brake disk on the exterior side, i.e. along its exterior edge.
The above-mentioned actual requirement, specifically, the indication of an axle for a passenger car that requires as little space as possible and, in particular, has a low overall height, can be met even better by way of a suspension strut axle according to the invention if a leaf spring element oriented at least partially in the transverse direction of the vehicle is provided as a supporting spring for the proportional support of the vehicle body on the wheel. The leaf spring element is supported on the one side at the above-mentioned control arm and, on the other side, directly or indirectly by the interposition of an axle support at the vehicle body. In this case, the use of a leaf spring as a supporting spring for a suspension strut axle is basically known; compare, for example, the above-mentioned German Patent Document DE 197 21 878 A1.
It is further provided here that no wheel guiding function be assigned to the leaf spring element, also called a “transverse leaf spring”, so that this transverse leaf spring can be dimensioned as a pure bending beam with a parabolic cross-sectional course. In this sense, the leaf spring element is preferably hinged to the control arm and is fixedly, with respect to moments, supported with its other end (at the vehicle body or at an axle support). Particularly for reducing weight, the leaf spring element may be constructed of a plastic material, particularly of a fiber-reinforced material.
Depending on the available space or as a function of other marginal conditions, a separate transverse leaf spring may be assigned to each wheel of an axle according to the invention, which transverse leaf spring may then also be oriented particularly in a sloped manner with respect to the transverse direction proportionally in the longitudinal direction of the vehicle. However, as an alternative, a joint single leaf spring element may be provided for the two wheels of the axle. In the latter case, the support of the joint leaf spring element with respect to the vehicle body may be constructed such that this leaf spring element at least proportionally takes over the function of a stabilizer, which is basically known; compare, for example, the above-mentioned German Patent Document DE 29 27 486.
If the suspension strut, which, in the top view, is fastened in front of the drive shaft of the wheel at the wheel carrier/pivot bearing, viewed in the transverse direction of the vehicle, starting from the wheel carrier, is sloped toward the rear and, as customary, is in addition sloped toward the interior, by means of the functionally predefined length of the suspension strut or of the shock absorber of the suspension strut, as a result of this quasi double sloping, a further reduction of the required overall height can be achieved. This is also indicated in an embodiment of the present invention which will be described in the following.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.